1. Field of the Invention
The present invention relates to superoxide dismutase derivatives, a method of producing the same, medicinal uses for said derivatives, and compositions containing said derivatives for oral administration.
2. Description of Prior Art
It is known that superoxide dismutase (hereinafter referred to briefly as SOD) is omnipresent in the living tissues of animals, plants and microorganisms and is an enzyme decomposing superoxide which is harmful to living organisms. Recently, attempts have been made to utilize isolated SOD as an antiinflammatory agent (FARUMASHIA, 17, 411, 1981 and Current Therapeutic Research, 16, 706, 1974).
It is also known that when SOD is administered intravenously, its plasma half-life is as short as 4 to 6 minutes and that the administered SOD is rapidly excreted. For prolonging the plasma half-life of SOD, an attempt has been made to modify SOD with Ficoll, polyethylene glycol, rat albumin or inulin [Japanese Published Unexamined Patent Application (Kokai Tokkyo Koho) No. 32826/83].
It has been reported that the SOD activity of Ficoll- or polyethylene glycol-modified SOD is drastically lower than that of unmodified SOD, while rat albumin-modified SOD is antigenic. It has also been found that inulin-modified SOD is considerably inferior to SOD in enzymatic activity.
It is an object of the invention to provide a novel superoxide dismutase derivative having a remarkably extended plasma half-life as compared with SOD while retaining the enzymatic activity of SOD substantially intact.
It is another object of the invention to provide a novel superoxide dismutase derivative which has pharmacological actions such as antiinflammatory action and so on and is safe.
It is a still another object of the invention to provide a method of producing said superoxide dismutase derivative.
It is a further object of the invention to provide medicinal uses, for example as an antiinflammatory drug, of said superoxide dismutase derivative.
It is still another object of the invention to provide compositions suitable for oral administration of said superoxide dismutase derivative.
These objects as well as other objects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description.